Arq-E; Arq-E3 - Wavecom W40PC Manual

The data proper is transmitted at a rate of 8 Baud. As the transmission rate is very low this
mode is insensitive to fading and multipath propagation.
A MFSK IAS will retrieve symbol clock. In order to process both baud rates used by AUM-13,
the IAS has to be configured to a baud rate of 16 Baud. Thus at a rate of 1 baud 16 symbols per
transmitted symbol, and at 8 Baud two symbols per transmitted symbol, must be received with
a certain tolerance. Even if for instance the same character is received 16 times in succession,
error correction is impossible due to the fact that in case of repetition of numerals the numeral
itself is followed by the repetition indicator.

ARQ-E

Parameter
Frequency range
System
Baudrate
Modulation
Receiver settings
Signal source(s)
Alphabet
The ARQ-E duplex systems operate at speeds of 46.2, 48, 50, 64, 72, 86, 96, 144, 184.6, 192
and 288 Baud on the radio link.
ARQ-E synchronization may be started by the selection of a baud rate. An "AUTO" program
start causes the automatic determination of the frequency shift and baud rate to be executed
first. The signal polarity (USB or LSB sidebands) is automatically detected.
After synchronization to an ARQ-E system has been achieved, the detected repetition rate is
displayed (4, 5 or 8 cycles). This parameter may give clues to the identity of the transmission.
If a continuously repeated character (often FFFF) is decoded whilst working in the ARQ-E
mode, it is most likely an ARQ-E3 system being monitored. ARQ-E employs the ARQ-1A
alphabet with parity checking which allows the detection of transmission errors.
For short-wave transmissions synchronous full duplex ARQ (Automatic Request) modes have
become very significant.
Full duplex systems transmit a RQ character after having detected an erroneous character or in
the presence of excessive signal distortions. The remote station subsequently repeats the last
three, four or seven characters preceded by the RQ character.
To maintain synchronization between the two stations both transmitters operate continuously
and send the idle bit pattern if no traffic is transmitted.

ARQ-E3

Parameter
Frequency range
System
Baudrate
Modulation
Receiver settings
Signal source(s)
Alphabet
120 • Transmission Modes
Value
HF
DUPLEX, Single channel
46.2 - 288.0 Baud, variable 30-650 Baud
SSB or DIRECT-FSK
CW, LSB or USB
AF, HF or IF
ITA-2 with parity and identification bit
Value
HF
DUPLEX, Single channel
48.0 - 288.0 Baud, variable 30-650 Baud
SSB or DIRECT-FSK
CW, LSB or USB
AF, HF or IF
ITA-3
WAVECOM Decoders v6.15 W40PC, W41PC, W51PC